Structural reliability analysis of multiple limit state functions using multi-input multi-output support vector machine

This paper presents a novel procedure based on first-order reliability method (FORM) for structural reliability analysis in the presence of random parameters and interval uncertain parameters. In the proposed formulation, the hybrid problem is reduced to standard reliability problems, where the limit state functions are defined only in terms of the random variables. Monte Carlo simulation (MCS) for hybrid reliability analysis (HRA) is presented, and it is shown that it requires a tremendous computational effort; FORM for HRA is more efficient but still demanding. The computational cost is significantly reduced through a simplified procedure, which gives good approximations of the design points, by requiring only three classical FORMs and one interval analysis (IA), developed herein through an optimization procedure. FORM for HRA and its simplified formulation achieve a much improved efficiency than MCS by several orders of magnitude, and it can thus be applied to real-world engineering problems. Representative examples of stochastic dynamic analysis and performance-based engineering are presented.

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On the Application of Structural Reliability Analysis

Volume 9: Offshore Geotechnics; Torgeir Moan Honoring Symposium ◽

10.1115/omae2017-62717 ◽

2017 ◽

Author(s):

Torfinn Hørte ◽

Gudfinnur Sigurdsson

Keyword(s):

Reliability Analysis ◽

Structural Engineering ◽

Structural Reliability ◽

Limit State ◽

Design Analysis ◽

Ultimate Limit State ◽

Hull Girder ◽

Structural Reliability Analysis ◽

Code Calibration ◽

Calculated Probability

Structural Reliability Analysis (SRA) is a useful tool in structural engineering. Uncertainty in input parameters and model uncertainties in the analysis predictions are explicitly modelled by random variables. With this methodology, the uncertainties involved are handled in a consistent and transparent way. Compared to a deterministic analysis, SRA provides improved insight in how the various uncertainties involved influence the results. The main results from SRA is the calculated probability of structural failure, but other useful results such as uncertainty importance factors and design points being the most likely combination of all variables at failure represent helpful information. The present paper illustrates some the features using SRA for two different types of application. The first application is the use of SRA as a tool for code calibration and the second shows the application of SRA to a problem where common practice is likely to be rather conservative and therefore leading to unacceptable results, but where the degree of conservatism is not known. Two examples are chosen to illustrate code calibration; i.e. hull girder ultimate limit state (ULS) for tankers and ULS for mooring design in the ULS for floating offshore vessels. Code calibration involves both SRA and design analysis following the code. It is shown how the design analysis can be modified in order to better reflect a chosen target reliability level across a selected set of test cases representative for what the code should cover. Fatigue of subsea wellhead systems is selected as an example of a special case when application of existing rules may lead to unsatisfactory results which are likely to be rather conservative. It is shown how results can be presented in terms of the accumulated probability of fatigue failure as a function of time. This may be a more suitable basis for decision making than a calculated fatigue life from a standard analysis. It is also illustrated how importance factors from the SRA can be used as guidance on how to prioritize effort in order to improve prediction of the fatigue damage. The present paper is not intended to be detailed in all input and analysis methodology, but draw the attention towards the possibilities and benefits of applying SRA in structural engineering, where the examples are used to illustrate this potential.

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NorMoor JIP, Structural Reliability Analysis for Mooring Lines in Ultimate and Accidental Limit State

10.4043/27734-ms ◽

2017 ◽

Author(s):

Torfinn Hørte ◽

Siril Okkenhaug ◽

Øivind Paulshus

Keyword(s):

Reliability Analysis ◽

Structural Reliability ◽

Limit State ◽

Mooring Lines ◽

Structural Reliability Analysis

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Reliability Analysis of Self-Anchored Suspension Bridge by Improved Response Surface Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.90-93.869 ◽

2011 ◽

Vol 90-93 ◽

pp. 869-873 ◽

Cited By ~ 1

Author(s):

Xiao Lin Yu ◽

Quan Sheng Yan

Keyword(s):

Reliability Analysis ◽

Response Surface ◽

Response Surface Method ◽

Structural Reliability ◽

Limit State ◽

Suspension Bridge ◽

Support Vector ◽

Surface Method ◽

Reliability Method ◽

Improved Response Surface Method

The response surface method (RSM) developed in recent years is an effective way to solve the structural reliability problems with implicit performance function. In order to improve the computational efficiency and make RSM suitable well to large and complex engineering structures, the reliability analysis method based on uniform design method (UDM) and support vector machine (SVM) was proposed. UDM is adopted to select training data and SVM is used as response surface. Structural reliability index is calculated in combination with the traditional reliability analysis methods (such as, the first-order reliability method (FORM), the second-order reliability method (SORM) or Monte Carlo simulation method (MCSM)). Numerical examples show that sampled with the UDM can greatly reduce the number of samples required for training by SVM model, and a very good approximation of the limit state surface can be obtained to get the failure probability. The reliability analysis of the under serviceability limit-state of a typical self-anchored suspension bridge——Sanchaji Bridge was carried out with the improved response surface method.

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